1. Field of the Invention
This invention relates to polyphenylene ether copolymers, and more particularly, to such copolymers obtained by oxidative coupling copolymerization of phenols and anilines, and having improved properties, such as improved heat resistance.
2. Description of the Prior Art
Polyphenylene ethers are high molecular compounds obtained by oxidative coupling polymerization of phenols, and generally have good mechanical properties. Particularly, themoplastic resins obtained by blending the polyphenylene ethers with polystyrene polymers, are widely used because of their balance of chemical, and physical properties, and for moldability.
Prior art polyphenylene ethers are, however, deficient in other respects, such as, for example, they are not always satisfactory in resistance to deterioration by heat or photo-oxidation.
Moreover, attempts have been made in the prior art to improve the mechanical properties of various engineering resins, by incorporating fibers or fillers therein. It is common to use such fibers or fillers for surface treatment to accomplish that purpose.
Polyphenylene ethers are usually prepared by dehydration and condensation of phenols by oxidative coupling as hereinabove stated. This is a special type of polycondensation reaction, and there is a limitation as to the applicable monomers to be used therein. The polyphenylene ether copolymers obtained by oxidative coupling, as heretofore proposed in the prior art, are all of the polyether structure. For example, they include halophenol copolymers, such as disclosed in Japanese Pat. Nos. 14833/1964 and 22269/1965; 2,3,6-trimethylphenol copolymers, such as disclosed in Japanese Pat. No. 17880/1977; cresol copolymers such as disclosed in Japanese Pat. No. 144097/1977; bisphenol copolymers such as disclosed in Japanese Pat. No. 5864/1976; naphthol copolymers such as disclosed in Japanese Pat. No. 104298/1975; and 2,6-diphenylphenol copolymers such as disclosed in Japanese Laid Open Patent Specification No. 56298/1978.